Public Health Twitter Journal Club will meet for live Twitter discussion on Tuesday 26th February, starting at 8.00 PM (GMT / UK time). All are welcome to contribute and pose questions using the hashtag #PHTwitJC. If you have never joined a Twitter chat before, there are some tips in the ‘About’ page linked above.
We will be discussing this research paper:
Adams J, Tyrrell R, Adamson AJ, White M (2012). Effect of Restrictions on Television Food Advertising to Children on Exposure to Advertisements for ‘Less Healthy’ Foods: Repeat Cross-Sectional Study. PLoS ONE 7(2): e31578 Full text link
The topic was selected as one that has recently been in the news, for example, here and here. The headlines were prompted by a report on obesity from the UK’s Academy of Royal Medical Colleges (AoMRC), Measuring Up. One of the ‘prescriptions’ for tackling obesity proposed in Measuring Up is a ban on unhealthy food advertisements before the TV watershed, i.e. before 9.00 pm, during family viewing hours.
An advertising industry representative and AoMRC spokesman debated the issues on BBC Radio 4’s Media Show, broadcast on 20th February 2013 (from 12 minutes in): Podcast link
This would further extend TV advertising restrictions that began to be brought in in the UK from 2007. It is currently not permitted to broadcast adverts for foodstuffs that are high in fat, salt or sugar (‘HFSS foods’) during children’s programmes or on children’s TV channels.
Our chosen paper examines one aspect of the impact of those restrictions, and asks whether this policy did indeed limit children’s exposure to advertising of HFSS foods.
The authors used a repeated cross-sectional design to study the profile of TV advertisements, and audience exposure to them. The study was conducted over one week in 2006 (before implementation of the restrictions), and over a second week in 2009 ( six months after full implementation of the restrictions). All adverts broadcast on all available channels in one region of the UK over each week, were included.
Adverts for foodstuffs were identified, and existing nutritional information about the products was used to identify the proportion of adverts that were for less healthy (HFSS) foods. Data from a well-established TV viewing panel were used to estimate the number of people (aged 4 and over); and the number of children (aged 4-15) exposed to the adverts. Person-minute-views (taking into account adverts’ differing lengths) were calculated for all adverts; food adverts, and HFSS food adverts. Pre- and post-restriction results were compared by calculating odds ratios.
Overall exposure (person-minute-views) to adverts for HFSS foods as a proportion of all advertising was higher in Week 2 than Week 1, for viewers as a whole. Restrictions had been adhered to such that in Week 2, there was almost no HFSS advertising on children’s channels or around children’s programmes. However, of food advertising actually watched by children, a higher proportion was for HFSS products in the post-implementation phase.
Questions for discussion:
- Were the aims of the study clearly defined?
- Was the study design appropriate to answer this research question, and adequately described?
- Were the methods of comparing and analysing clear and appropriate?
- What are the implications of the study for public health policy?
- What future research might be needed in the area of children’s exposure to TV advertising of less healthy foods?